Double-spring gage.



' TED STATES PATENT OFFICE.

COLEMAN J. MANNING, 0F MEDFORD, MASSACHUSETTS, ASSIGNOR TO AMERICAN STEAM GAUGE .85 VALVE MANUFACTURING COMPANY, OF BOSTON, MASSACHUSETTS,

A CORPORATION 0F NEW JERSEY.

DOUBLE-SPRING GAGE.

Specification of Letters Patent.

Patented JulyT 25, 1916.

To aZZ whom t may concern.'

Be it known that I, COLEMAN J. MANNING, a citizen of the United States, and resident of Medford, in the county of Middlesex and State of Massachusetts, have invented certain new and useful Improvements in Double-Spring Gages, of whichthe following is a specification.4

This invention relates to gages for measuring fluid pressures in which there are a plurality of opposed spring tubes operating in combination to give movement to the indicating device.

The object of the invention is to overcome certain objections inherent in double spring gages as heretofore produced and to secure greater certainty and ease of operation with less wear of moving parts, less vibration of the indicator, and reduced cost of manufacture.

Briefly stated the fundamental idea of the invention is that of carrying the movement by which the indicator is operated bodily upon one of the spring tubes and providing an actuating connection between the movement and the other of such tubes.

In the accompanying drawings I have shown the preferred embodiment of the present invention.

Figure l is a front elevation of a gage in which my invention is incorporated, the glass face, the dial, and the indicating element being removed. Fig. 2 is a' side elevati on of the internal mechanism of the gage as seen from the right of Fig. l, the case being shown in section. Fig. 3 is a section on line 3--3 of Fig. l, looking in the direction of the arrow. Fig. l isa rear elevation of the mechanism of the gage, the case being sectioned on line 4 4 of Fig. 3.

The same reference characters indicate the same parts in all the figures.

' In the drawings a represents the caseof a gage having the usual form or any other desired character.

Z) and c represent two spring tubes of the Bourdon type, such tubes being both connected 'with a head (Z, which is secured to the case and has a nipple c passing through the bottom wall of the case and threaded for connection with a fluid conduit. The spring tubes are hermetically sealed in the head and are in communication with the passage f which leads through the nipple c into the head. The tubes b and c are formed with a permanent curvature so that when the pressure within them is dierent from that of the atmosphere they tend either to become less or more curved according as the internal pressure is greater or less than atmospheric. They are arranged in opposed relation, extending oppositely from the head and with their free ends brought toward one another, so that when subjected to an increase or reduction of internal fluid pressure such free ends move away from or toward one another, respectively.

It is to be understood that the gage is to be equipped with any common or desired type of dial orrecord sheet, which is not here shown, and that cooperating with such dial or sheet there is an indicating member, or indicator, such as a hand, pointer, or marker, or the like, also omitted from the drawing. The indicating member is mounted upon a center staff or arbor g, which has bearings in a movement frame consisting of a plate or bridge and a plate c', said `plates being secured together at a proper distance apart by posts y' and screws 7c. The staff g forms part of the movement for Aactuating the indicating member or pointer, the rest of the movement consisting of a gear segment Z, secured upon a staff m which has bearings inthe movement frame, a gear pinion n on the staff g, with which thesegment meshes, anda hair spring o, connected with the st alf g and with the rpost j, for returning the 1ndicator to normal position and for taking up back lash between the pinion and segment.

The movement frame instead of being secured directly to the case, as is the usual practice, is carried by one of the spring tubes, as c, being mounted upon a plate or holder p which has a lug g preferably soldered to the end of the spring tube c and closing the opening in suchend. Such lug g may-be secured in the same rmanner and perform the same function as the head which is ordinarily put on the end' of a Bourdon tube. An actuating connection between the other spring tube Z) and the segment Z is made by a link 7' pivoted to the free end of the tube b and pivoted also to a slotted bar s secured to the segment Z by a screw t which passes through the slot of the bar into the segment and has a head overly-V ing the bar. Said bar is thus adjustable longitudinally on the segment, and provides a lever arm of variable length by which the connection between the link r and the segment may be made at a point more or less distant from the pivot m of the segment. l/Vhen fluid under pressure is admitted to both spring tubes their ends move apart, carrying the segment pivot in one direction and the actuating arm s in a dilferent direction, thus combining their movements to give a wider swingto the segment than can be given by either alone.

The range of movement given to the indicator for a specific pressure change is regulated by adjustments of the arm s in or out from the pivot. A further adjustment for altering the position of the indicator without changing its amplitude of swing is afforded by the means by which the movement frame is connected'with the holder 79. This connection is madeby two screws a and v, the former of which passes through a round hole in the movement plate c' at a point rel-atively near the staff g and the other of which passes through a slot in plate z'. The line from the segment pivot to the pivot screw u is substantially perpendicular to the link arm and thus this adjustment produces a movement of the segment about its axis of rotation and changes the limits of the swing of the indicator.

By mounting the movement frame as a whole on one of the spring tubes so that it is caused to move with the latter, the full extent of movement capable of being given to the indicator by a pair of opposed springs is produced without requiring a. large number of pivots, which are liable to shake and wear loose in consequence of movement of the tubes. In fact thererare only two pivots in all the actuating connections for the movement, instead of four or five heretofore always found necessary in double spring gages. The pivot screws in a. pressure gage are a source of error because, from the vibra.- tion incident to the use ofthe gage, they wear and shake loose, consequently a reduction in the number of pivot screws occasions a reduction in the amount of looseness and the rapidity with which looseness develops. All the parts of the movement, the movement frame, and the movement frame holder are made either of the same material, or of materials having the same coeflicient of expansion. This, together with the fact that the movement frame is carried by 'the spring tube instead of being mounted upony the back of the case, avoids all distortion of the frame and movement due to expansionV and contraction with variations of temperature. l/Vhere the movement frame is mounted upon the case, and the case has a difliculty because all parts of the movement frame and holder expand equally, and they are entirely free of the case. There is also a circulation of the air between the movement frame holder and the case, whereby the movement frame is insulated from the case and is not subjected to such great and rapid changes of temperature.

There is less vibration of the movementV frame under conditions of use, because the vibrations of the case are not imparted directly to the frame but are absorbed by the spring tube on which the frame is mounted.

The mounting of the frame on the holder p in such a way that theentire frame may be adjusted, allows the pivot of the segment to be held in the frame without possibility of transverse movement, while at the same time it can rotate freely and can be adjusted. This tends to increased accuracy and eliminates a cause of error and derangement heretofore existent in pressure gages.

Y I claim:

l. A pressure gage comprising oppositely arranged 'spring tubes 'adapted to receive the fluid of which the pressure is to be measured, a pointer actuating movement including motion-accelerating gearing carried by one of said tubes, and an actuating connection between said movement 'and the other of said tubes 2. A double spring gage for measuring fluid pressures, comprising'a pair of oppositely arranged curved spring tubes, a

movement frame secured to the free end of one of said tubes and movable therewith, an indicator-operating movement mounted in said frame, and an actuating connection extending to said movement from the free end of the other tube.

3. A pressure gage comprising a pair of spring tubes, a holder secured to one of said tubes, a movement frame mounted upon said holder, any indicator actuating movement held in said frame and including a pivot-ally mounted segment, and a link connected with the other of said tubes and with said segment eccentrically of the pivot of the latter. Y

t.v A pressure gage comprising a pair of spring tubes, a holder secured to one of said tubes, a movement frame mounted upon said holder, an indicator actuating movement held in said frame and including a pivotally mounted segment, and a link connected with the other of saidftubes and with said segment eccentrically of ther pivot of the latter, said movement frame being adjustable on the holder in such manner that the part carrying the pivot of the t segment may be moved toward or from said other spring tube.

5. A pressure gage comprising two curved spring tubes each adapted to receive the same Huid, a case inclosing said tubes, an indicator actuating movement, a frame connecting the parts of said movement, an aetuating connection between said movement and one of the tubes, and means by which said movement is carried bodily by the other tube, the movement and its frame being otherwise separated from the case.

6. A pressure gage comprising two oppositely arranged curved spring tubes, a head to which both tubes are connected and through which both are connected with the same pressure Huid, a holder secured to the free end of one of said tubes, a movement frame, an indicator movement carried by said frame including a pivotally mounted segment having an arm, means for adjustably connecting said movement frame to said holder, consisting of a pivot stud at a point on the frame relatively remote from the segment pivot, and clamping means for securing the frame to the holder in various positions about said pivot stud, and a link extending from the other of said spring tubes to said segment arm, the said link and segment arm being approximately at right angles, and the line from the segment pivot to the pivot stud of the movement frame being transverse to the direction of the link, whereby the adjustment of the movement frame alters the path of movement of the segment indicator without changing the amplitude of such movement under given pressure changes.

7. In a pressure gage the combination with a pair of oppositely arranged spring tubes, a movement for actuating the indicator of the gage, a movement frame supporting said movement, a holder connected other of said tubes, the movement frame and holder being of materials of the same coefficient expansion, whereby the movement frame may expand and contract under temperature changes without distortion.

8. In a pressure gage the combination with a pair of oppositely arranged spring tubes, a movement for actuating the indicator of the gage, a movement rame supporting said movement, a case inclosing said springs and movement, an actuating connection from one of said tubes to said movement, and means connecting said movement frame to the other of said springs, the last named spring supporting the movement frame. independently of the case, whereby the movement frame is unaffected by expansion and contractionof the case or by vibration of the case.

9. A gage for measuring fluid pressures comprising a plurality of oppositely arranged pressure controlled members adapted to be acted upon by fluid and to be distorted when the pressure of such fluid is diferent from that of the atmosphere, an indicator-operating device carried by one of said members, and means connected with said device and having also a connection with the other of said members for causing said device to be moved when the members are distorted.

In testimony whereof I have afiiXed my signature, in presence of two witnesses.

COLEMAN J. MANN ING.

IVitnesses:

C. F. BROWN, E. BATCHELDER.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, D. C. 

